We used the Amby bed with kiddo #1, and really liked it. I kept it right by my side of the bed and would just put her back in after she nursed. Easy to reach from lying down in bed, and if she stirred during the night, sometimes giving the bed a little bounce would get her back to sleep.
I have heard that the sheets shrink (even the non-natural cotton). We just wrapped a fleece blanket around the "mattress" (tightly) and tucked it under so there was an extra layer of protection for the mattress. Never had any problem. Just swaddled her to keep her warm. I have heard of people making their own sheets as well.
I guess we'll be using it again soon, too. (Just found out we're expecting #2).